A new intersection design eliminates the dreaded left turn into traffic

Anyone who has ever made a left turn in a busy intersection
understands that it can be a stressful maneuver. Not only do you
have to wait impatiently for a break in the stream of cars
coming the opposite direction, you often hold up a line
of traffic, and even risk getting into a collision if other
drivers aren’t following the rules of the road.

But despite how standard it may seem to turn left into
traffic, that's actually not an inevitable part of driving.
There's an intersection design that could save you all
that trouble.

The “diverging diamond
interchange” creates designated ramps that gradually direct
cars to veer left or right, without ever requiring them to cross
in front of ongoing traffic.

Though it might look complicated, it’s actually a simple
concept. Say, for example, that you’re driving from west to
east. As you come to the intersection, a red light may stop you
as you let cars going the other way pass. (This is the only time
streams of traffic cross each other.) If you want to turn
right, a lane peels off and merges with the road carrying
southbound cars. If you want to turn left, you just follow the
ramp that veers to the north.

Watch it in action:

Since 2009, this diamond design has been implemented in 62
intersections across 22 US states,
according to Wired.

And it’s working: In a recent study comparing
crash data from before and after a series of intersections were
converted to the new design, researchers found that overall
crashes were reduced by 33%, while crashes that result in injury
were reduced by 41%.

The diverging diamond was popularized in the US by Gilbert
Chlewicki, the founder of Advanced Transportation
Solutions, a transportation planning and design firm.
Chlewicki wrote a term paper about the concept as a graduate
student in 2000, and has devoted much of his life’s work to
promoting the design ever since. He’s published several papers
about it and has presented at conferences throughout the United
States and Canada.

The first diamond interchange in the US was built in
Springfield, Missouri in 2009 (France has had a
few since the 1970s) and Chlewicki attended the ribbon
cutting. In a survey conducted there later, 95% of drivers
surveyed said there has been less traffic congestion since the
new intersection opened, and 97% said they felt safer.

According to a map on
Chlewicki’s official website for the design, many more such
intersections are currently being planned and constructed,
mostly in Midwestern states. The rest of the country's
commuters will have to continue suffering through regular
left turns until the trend catches on elsewhere.